CI: switch to virtme-ng

[matttbe]

virtme is no longer maintained. virtme-ng bring many new features, fixes and is quicker (e.g. using virtiofs, init script, microvm, etc.) and it is also used by the new Netdev CI.

[geliangtang]

Matt, I can assist you in implementing this.

[matttbe]

@geliangtang thank you for this suggestion.

I started to look at it, I have some uncommited code. I will try to look at it this week and share code. Then we can see what can be done from there if that's OK.